During the manufacture and assembly of electronic display devices, such as for example cathode ray tube (CRT) assemblies for computer monitors and television sets, precise mechanical, optical and electronic adjustments are required to ensure the electronic display devices provide optimum reproduction image quality. These adjustments include, but are not limited to, focus, purity of color, convergence of beams, color uniformity, geometry, and luminance. Each of these adjustments is typically performed independently of the others by a trained technician with the aid of a testing and alignment system. Unfortunately, many testing and alignment systems are deficient because they are unable to perform all of the tests needed to align precisely a CRT assembly, are very slow and unable to provide real-time feedback for operator adjustments, are not sufficiently accurate and are not integrated to perform each of the tests in an optimized sequence and then recheck and readjust measurements as required.
To deal with the above-described problems, improved test and alignment systems for electronic display devices have been developed. For example, PCT application serial No. PCT/CA95/00352 published on Dec. 21, 1995 and assigned to Image Processing Systems Inc., the assignee of the present invention, discloses a test and alignment system for electronic display devices. The system includes a plurality of color CCD cameras mounted on a frame and arranged in an array. The rows of CCD cameras in the array are vertically adjustable and the CCD cameras in each row are laterally adjustable to allow the system to test and align different sized electronic display devices. The image output of the CCD cameras is conveyed to a computer for processing. The computer controls a test pattern generator connected to the electronic display device being tested so that the electronic display device displays appropriate test patterns of which images are captured by the CCD cameras. A wobulator is mounted on the frame and is moveable between an operable position adjacent the electronic display device and a retracted position outside of the fields of view of the CCD cameras. The wobulator is energizable to bend electron beams within the electronic display device when in the operable position. Photodiodes, also mounted on the frame, measure the luminance of the electronic display device as the wobulator bends the electron beams therein and provide input to the computer for processing.
The computer performs a comprehensive series of test and alignment functions on the electronic display device based on the image output of the CCD cameras and the output of the photodiodes as the test patterns are displayed. The test and alignment functions include color purity, focus, static and dynamic convergence, yolk rotation, orthogonality, video pattern size and centering, raster size and centering, linearity, geometry and luminance measurements and are all performed at a single station. During the series of test and alignment functions, the computer displays graphical indicators which are used by an operator to determine if the electronic display device passes or fails a test.
U.K. patent application No. 2,255,700 published on Nov. 11, 1992 and assigned to Samsung Electron Devices Company Ltd. discloses a system for measuring cathode ray tube (CRT) characteristics. The system comprises a camera, a selector, a video processor, a monitor, a magnetic field controller, a CPU and an output unit. The camera includes an array of CCD cameras as well as a plurality of magnetic field coils which are energized by the magnetic field controller under control of the CPU to move an electron beam within the CRT. Image output of the CCD cameras is conveyed to the CPU for processing. In one embodiment, the CCD cameras are movably mounted on a support to allow the position of the CCD cameras relative to the CRT under examination to be adjusted.
Although the above-described references show test and alignment systems for electronic display devices including a plurality of CCD cameras which are moveable relative to the electronic display device under examination and allow at least one characteristic of the electronic display device to be measured, improved systems for testing and aligning electronic display devices are continually being sought.
It is therefore an object of the present invention to provide a novel test and alignment system for an electronic display device and a test fixture for the same.